Normally, the feed roll on a carding machine is driven by a small beveled draft gear which meshes with a large beveled gear having a diameter, for example, of approximately 13 inches which is mounted on the feed roll drive shaft. Such a drive arrangement is shown in U.S. Pat. No. 1,512,267. Normally, these gears are cast and are not precision gears producing uneven wearing and warpage of the gears in continued operation. To provide a precision gear the size of the large diameter gear would require a skilled machinist at a high cost.
The feed roll operates to feed the cotton to the main cylinder of the carding machine and it is desirable that the feed roll operate at a slow and constant speed so as to feed the cotton at a low rate of constant speed into the card so that the card has sufficient time in which to spread the cotton into an even sheet for uniformly charging the main cylinder. The above mentioned warping and uneven wearing of the conventional drive arrangements often produces variations in the speed at which the feed roller is driven, and it has not been possible to control the speed of the feed roller accurately.
In addition, it is often desirable to change the speed at which the feed roll is driven by replacing the small draft gear and the large beveled gear as a matched pair with a pair of gears of different gear ratio. However, a large beveled gear of such size, even when made by casting involves considerable cost and coupled with the fact that such a gear often becomes unevenly worn or warped results in an undesirable drive arrangement.